CBSE Class 12-science Answered

For every moving charge there is a current density which produces a magnetic field. The Biot-Savart law gives the magnetic field as being an inverse square law, just like Coulomb's law in electrostatics, and at a point it is at right angles to the line joining the current element to that point as well as the direction of the current which is producing the field.

When a charged particle is not moving the electric field
lines emanate from the charge outward in all directions and until we move the
charge we might think this is the only kind of field that the charge can
create.  When the charge moves, we find that there is the possibility for a
new kind of field that can have lines which do not start or end on charges,
but which can form closed loops.  These are the magnetic field lines.  As soon
as there is movement of the charges, there are time changes of the electric
fields, and that can produce magnetic fields.